Strep and Mono: Bonnie & Clyde or Crips & Bloods?

A recent study published in the Journal of Infectious Diseases provides a great illustration of the intricate interplay between humans and 2 microbes, highlighting how pathogens interact with each other in order to facilitate their spread. 

The study is focused on the interaction between Group A streptococcus (GAS)--the cause of "strep throat"--and Epstein-Barr Virus (EBV), the cause of infectious mononucleosis.

As 20% of children are colonized with Group A streptococcus and EBV persistently infects 90% of the population, the two pathogens may have important influences on each other given that both of their habitats are the oropharynx.

EBV infects cells in two manners, lytically and latentenly. The lytic type of infection results in active viral replication, viral shedding and cell death facilitating spread. The latent type of infection, on the other hand, is relatively quiescent. Understanding what causes the switch from latency to a lytic infection is of great interest.

In this study, it was determined that GAS colonization can prompt EBV to emerge from latency and become lytic and enhance its presence in saliva thereby increasing the likelihood that it will spread to other humans. 

I think that this paper is fascinating because it highlights the fact that pathogens interact, not only with the host, but, with each other in an elaborate manner that impacts transmission. 

EBV's exploitation of GAS colonization is akin to one criminal exploiting the distraction that the presence of a rival criminal creates to go on a crime spree of contagion. Or maybe they're more like Bonnie and Clyde? 

Allergic to Allergies

As an infectious disease physician, I prescribe a lot of antibiotics for various conditions. Some are minor infection and some are life-threatening. One of my pet-peeves are antibiotic "allergies" that are not true allergies. While people may genuinely have anaphylaxis to an antibiotic, the majority of "allergies" that I deal with do not even result in a rash.

What underlies the disparate meanings of allergy is a misconception regarding what constitutes a true allergy. The word allergy derives from the Greek words allos and ergon and, literally translated, means other activity. In effect, a medication or substance (e.g. poison ivy) creates a reaction other than the one expected. 

In modern medical parlance an allergy refers to a hypersensivity to a substance by the immune system. This is manifested by hives, swelling of certain body parts, difficulty breathing, difficulty swallowing, and shock. Nausea, vomiting, headaches, abdominal pain, diarrhea, and anxiety are not the result of allergies. They are known side effects of certain medications and do not usually preclude their use unless truly severe or debilitating. 

When an individual reports an unknown "allergy" to say penicillin ("My mom said I had a reaction to penicillin of some sort when I was a baby"), healthcare providers do one of two things: ascertain whether this was a true allergy or pick another drug--the usual reaction. Often, the alternative drug is more expensive, not as effective, side effect prone, and broader in terms of antimicrobial spectrum than needed. 

Reclassifying those without true antibiotic allergies would go a long way towards improving antibiotic stewardship. 

The Creature from Norwalk Ohio

Today CNN is reporting an outbreak of norovirus on a Royal Caribbean cruise ship. Thus far, 66 individuals have been infected.  

This virus, named for the city in which it was first discovered (Norwalk, OH), is the most common cause of acute gastroenteritis, colloquially known as "stomach flu", in the US, where it causes over 20 million infections annually.

Norovirus outbreaks on cruise ships (and in other locales, including national parks) are nothing new but pose huge societal problems because of the disruptions that ensue upon their arrival. When norovirus strikes--this, I know from personal experience--24 hours of so of one's life are going to be spent in the bathroom. 

While the diarrhea is bad, it is the violent vomiting--which often seizes one suddenly--that, to me, is the worst aspect of this dreaded disease. The vomitus (what is vomited up) is highly infectious and hand washing with alcohol-based substances alone may not be enough to deactivate the virus.

There are no vaccines or anti-viral treatments for norovirus, though anti-nausea medications (e.g. Zofran) can be lifesavers. 

Too bad there isn't a special "vomit powder", similar to what the maintenance staff would sprinkle on our vomit in school, for this despised virus. 

Gag Me With A Fungus: (San Joaquin) Valley Girls

I was happily surprised to find a long and informative article by Dana Goodyear on Cocciodiomycosis in the January 20, 2014 issue of The New Yorker. The piece is focused on the impact this infectious disease has had on California's San Joaquin Valley from which its second name, Valley Fever, is derived. 

This disease, caused by the fungi Coccidioides immitis, can cause a wide spectrum of illness ranging from asymptomatic infection to pneumonia to fulminant life threatening presentations, including meningitis. Goodyear importantly mentions the fact that the organism was considered as a potential bioweapon and was, until recently, considered a Select Agent--a designation that prompts a high degree of oversight by the government. 

I find several aspects of Cocciodiomycosis to be fascinating including its temporal association with earthquakes (which kicks up its spores), the varied symptoms elicited, and the predisposition Fillipinos have for severe cases.

Living and practicing medicine in Pittsburgh (The Mon and Ohio River Valleys), Cocciodiomycosis and the San Joaquin Valley are thousands of miles of away however, because patients travel, I have considered the diagnosis in select patients.

Don't Get Too Wound Up About Synthetic Biology

I just finished the book The Windup Girl  by Paolo Bacigalupi a dystopian novel set in the future.  The book was recommended by a physician colleague who knew of my interest in bioterrorism and plagues. 

The story of The Windup Girl revolves around agricultural company executives who produce engineered foods ("calorie men"), corrupt government officials, and an engineered human (aka a windup girl) winding there ways through a futuristic Thailand.

The book mentions past plagues that have destroyed crops (e.g. blister rust, cibiscosis) and infected humans leading "generippers" to utilize the tools of synthetic biology to devise new organisms (including humans) resistant to these pathogens. An outbreak of a new disease also transpires leading government officials to take action in a village in which victims resided. 

I found the book to be engaging despite the fact that, at times, it was reminiscent of Frankenstein in its depiction of "excesses" of industrial society and skewed portrayal of the promise of synthetic biology.

However, bioterrorism directed at agriculture is not fictional and is a major concern. Not only can agricultural products be used as vehicles to deliver noxious substances (e.g. mercury injected into citrus fruits), but contaminating them with specific pathogens can lead to food shortages and major economic disruptions.

The promise of crops, animals, and--eventually--humans impervious to infection would be an unequivocal life-enhancing utopian development.

While some may see these developments leading to a dystopian future, I believe it is fictional.